The new MSB Pro USB interface

Comments

Sablon Audio

Industry Expert, VIP Donor
May 22, 2015
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#21
Really nice to know some thechnical details of the ProUSB. Scrambling data in serial links seems a good move - it was done long ago by Ben Duncan (Audio Synthesis) using a proprietary SPDIF link - the Transcend N-Code. However I would not expect that such a link would need redundancy and detection codes - bit rates are tens of Mbit/s maximum - unless very long lengths are considered. Can I ask what is the typical corrected error rate?
I used to own the Audio Synthesis Transcend / Dax Discrete Variable combo and they used a dual ST optical interface named ASL. Not sure of Ben Duncan's involvement however the AS owner was David Heaton. Beautiful build quality and a good company to deal with.
 

ferenc_k

New Member
Apr 9, 2011
29
0
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#22
I used to own the Audio Synthesis Transcend / Dax Discrete Variable combo and they used a dual ST optical interface named ASL. Not sure of Ben Duncan's involvement however the AS owner was David Heaton. Beautiful build quality and a good company to deal with.

I think there was an ST optical connection for the Theta Digital Generation III or V?
 

Sablon Audio

Industry Expert, VIP Donor
May 22, 2015
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#23
Quite possibly, it was a higher quality option than Toslink, though the AS implementation was a bespoke one using twin ST cables.
 
May 30, 2010
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#24
I think there was an ST optical connection for the Theta Digital Generation III or V?

Yes, at some point several brands were using the ST optical with ATT interfaces - DIY people as me fitted common transports with add on boards with the ATT ST ODL optical transceiver . Audio Synthesis even sold one board fitted with a quality discrete clock that would syncronyze the data and feed the clock back to the player circuitry, replacing the original clock.

A few brands, such as Krell, Audio Synthesis and Sony, had a dual ST interface also sending the DAC clock to the transport or vice-versa.
 
Jul 25, 2016
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#25
I had the Audio Synthesis modded universal transport and DAX Discrete too. Dual optical digital outputs sent enough digital data for SACD and DVDA discs. Single digital optical for the DAX Decade.
 

Taiko Audio

Industry Expert
Feb 10, 2017
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taikoaudio.com
#26
I've owned several Wadia models using ST interfaces. The good old Genesis Digital Lens had one too and was compatible with Wadia.
 

Taiko Audio

Industry Expert
Feb 10, 2017
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taikoaudio.com
#27
Quoting this message from the Computer Audiophile forums as it has some more relevant information then was posted here:

I’m from MSB Technology and I would like to share a few of the technical advantages the Pro ISL interface (and Pro USB) has over other digital audio interfaces. The only downsides of the Pro ISL interface are 2W of power consumption and compatibility only with MSB DACs.


DAC syncronous scrambled streaming data. Clocking of the data stream is syncronized to the DAC with a separate clock feedback link in a second fiber. Unlike block based protocols like Ethernet or USB, the Pro ISL interface does not generate electical noise in the audible band upon reception.



Strong forward error correction (optionally traded for more audio data channels) instantly corrects most errors including up to 1024 bit gaps in the audio data stream upon reception.



Very strong CRC based error detection (an HD8 CRC polynomial protects each 64 bits of audio data, an HD10 CRC polynomial for misc data). Allows quick identification of failing links and prevents playback of erroneous data.



Less than 10 milliseconds to lock to an active data stream.



Very low noise reception due to very low noise hardware decoding, data stream scrambling and balancing. Ethernet for example requires a complex operating system and usually an electrically noisy general purpose processor for reception and decoding. Ethernet, even optical Ethernet, also uses large asyncronous data blocks that generate much low frequency noise during decoding.



Perfect isolation from the non conductive single mode glass fiber.



Greater than 1km cable lengths are possible. Also no EMI radiation or conduction due to non conductive cabling. Cabling is safe safe to run anywhere because it is non conductive.



Much lower received jitter than any other digital audio interface. Cabling even at extreme lengths adds almost no jitter because single mode glass fiber cable has nearly zero dispersion and extreamly low attenuation of the modulated infrared laser light.



Supports 12 channels of 32bit/768Khz PCM data with forward error correction or many more channels without. Supports up to 32bit/3Mhz 2 channel PCM data. Supports 8 channels of 16x native DSD. Support for data stream format extensions for future data formats. Simple mailbox style communication channel for misc information. Strong CRC based error detection for all data. The Pro USB uses just a subset of the complete capabilities of the Pro ISL interface so it is ready for future expansion.



The Pro USB is as easy to install and configure as any other of our USB interfaces.
 
Likes: asiufy
May 30, 2010
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#28
Quoting this message from the Computer Audiophile forums as it has some more relevant information then was posted here:
Well, considering your insistence and enthusiasm I find I should now ask the inescapable question - should we expect that the Pro ISL interface (and Pro USB) creates a system immune to server quality?
 

Taiko Audio

Industry Expert
Feb 10, 2017
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taikoaudio.com
#29
Well, considering your insistence and enthusiasm I find I should now ask the inescapable question - should we expect that the Pro ISL interface (and Pro USB) creates a system immune to server quality?
Now that would be something! However, from what I have witnessed, I strongly doubt it.
 

CKKeung

Well-Known Member
Jun 18, 2011
1,167
282
83
Hong Kong
#30
Likes: Taiko Audio

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
7,514
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#31
i visited both rooms at Axpona with MSB Select II's twice.

in the room with the CH amps (upper picture), i did hear CD on the transport compared to higher rez (24/88) from a file. it was not the same recording so the value of the compare is marginal, but to my ears i preferred the higher rez file. i recognized what the higher rez does in my room compared to redbook files (which are still fantastic in their own right). assume it was using the i2s Pro interface. but i did not ask about that as no one in that room seemed to know much about the MSB (when i was present).

in the lower picture with the MSB amps, we never did any A/B with and without the new interface, so impossible to comment on it's contribution. prior to the show i had spoken to Vince about him sending me the Pro USB module to compare to my Renderer v2 and regular USB in my system. when that happens i will comment.

it was great to see Vince again. preferred the overall sound of Vince's room......but preferred the digital in these 2 rooms over any others i heard at the show......big surprise ;) (for whatever that is worth at a show).

as an aside; i asked Vince about the new MSB amplifiers, he said they will debut at Munich, and the timing did not work to have them at Axpona and get to Munich on time.

Sel-2.jpg

Sel-1.jpg
 
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CKKeung

Well-Known Member
Jun 18, 2011
1,167
282
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Hong Kong
#32
Thanks Mike!
 
Apr 3, 2017
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#34
The external ProUSB interface and internal module for my Select II DAC will be arriving at the end of May - looking forwards to enjoying the benefits of optical noise isolation and re-clocking of data packets to my Femto33 clock’s tick-tock !
 
Jan 23, 2018
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#35
I've ever heard Select2-Renderer and Select2-ProUSB with Aurender.
I think ProUSB is perfect clock sync solution from audio data(PCM) geterated to R2R dac.
Eventhouh the listening result was not good at that time, I believe we have to notice this solution.
 
Apr 3, 2017
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Hong Kong
#36
Just received the Pro USB / ISL modules, and it works - together with my Aurender W20 ! Previously, I've had months of problems getting a handshake and data lock between the W20 and the Quad USB input module. Looking forward to some critical listening sessions in the coming weeks. :)
 

Attachments

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Feb 10, 2017
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taikoaudio.com
#37
Copying here from the Extreme thread as it's useful information for MSB Pro USB owners:

Removing unused modules do not affect the sound of the DAC unless they are connected to cables “Except” the Renderer module. That module is a computer and needs to be on and active continuously so it can be ready to connect to a network. Removing it definitely has sonic benefits. Most people only either need the Renderer or the ProUSB so having only one plugged in is the best solution. It is possible to power down the Renderer from software but it would be a huge headache from a customer service perspective. From past experience we would get a rash of “failed” Renderer modules from customers who forgot they disabled them.
As you many have noticed the ProISL system uses SFP modules. The ProISL is not however related to any computer protocol like Ethernet, so the SFP modules that work well with ProISL will be different than the one that work well with Ethernet. Use only optical modules that meet these specifications: 1310nm laser, SMF (Single Mode Fiber), LC duplex connectors, TX laser power can not exceed -3dbm (or you run the risk of burning out the receiver die). Many SFP modules were evaluated and they all worked, we selected the ones that worked the best, "however" there may be some combinations of SFP modules that do not work. Since the ProISL is significantly different from any other data protocol used with SFP modules any experience with which SFP modules work best in another application will not track with the ProISL. The ProISL was designed to allow hot swapping of the SFP laser modules ONLY, NEVER hot swap the entire ProISL input module! Always power down the DAC to remove or add any input module. Failing to power down the DAC when unplugging or adding a module could ruin the DACs motherboard.
 
Feb 10, 2017
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taikoaudio.com
#38
1550nm modules do work for the ProISL, however they are not optimal for this application. If you wanted a custom link to send ProISL more than 20km I would recommend 1550nm due to its lower adsorption loss. The drawbacks are that under 20km 1550nm has much (in theory and measured by us) higher jitter than 1310nm. This is due to two factors. One, the lasers for 1310nm are more stable at room temperature and two, 1310nm has near zero dispersion (dispersion directly adds jitter) in SMF (Single Mode Fiber). We have verified this in our lab and for the shorter links most likely encountered in use 1310nm had much better jitter performance. While 1550nm may be best for a computer data link (where all you need is error free data transfer) it is not optimal for the ProISL. As in pointed out in my previous post, ProISL is much different from other computer data links so your experience with them will not track. So while 1550nm has less adsorption loss in SMF for long (kilometer length) cables that loss is near zero for 1310nm over short cable lengths. The advantage of near zero dispersion and better laser stability of 1310nm create a much higher performance ProISL link for shorter cables of less than a few kilometers. Also if a customer decided to use 1550nm at one end of the link and 1310nm at the other end it would still work if the cable was reasonably short but the performance would be much degraded leading to a semi incompatibility that would be hard to diagnose.
 

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